Income taxes - Provision for income taxes (Details) - USD ($)	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ 430,116	$ 202,444
State	(29,157)	(895)
Total	400,959	201,549
Deferred:
Federal	(184,469)	(524,733)
State	180,249	(124,798)
Total	(4,220)	(649,531)
Total provision (benefit)	$ 396,739	$ (447,982)

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